This invention relates in general to vehicle axles and more particularly to wheel drive axles.
Axle shafts are used to connect a driving and a driven member, such as the differential of an automotive vehicle and a driven wheel. Axle shafts, particularly for automotive vehicles, typically are formed of solid metal shafts with their opposite ends formed for connecting to the drive and driven members of the vehicle. For example, a flange may be forged or welded onto one end of the shaft for connection to a wheel hub, while the opposite end of the shaft may be provided with a spline for connection to a differential gear. Because such shafts must transmit considerable torque and are subjected to rapid starts and stops of power transmission, they must be rigid and strong enough to perform under both normal and overload conditions. Typically, axle shafts are formed from solid steel bar or rod to provide the required strength and rigidity.
In an effort to reduce cost and weight, hollow axle shafts have been used in the past with a wheel driving flange friction welded to the outer or wheel end of the shaft and a spline provided on the opposite end by a cutting, broaching or similar process. Unfortunately, much of the cost benefit of using a hollow shaft is lost using a typical friction welding process to attach a wheel driving flange. Wheel driving flanges have been connected to hollow shafts through splines, but these designs have been complicated and not viable due to the structural problems in strength and rigidity and maintaining the axial position of the wheel driving flange.
It would be desirable to provide a simple lightweight shaft with a wheel drive flange which can be cost effectively manufactured and which provides sufficient rigidity and torque carrying capacity.